[Cashtab] Lazy loading for agora

Summary:
Depends on D17499

Getting to the point where the page is unusable, esp by a new user with no tokens cached.

There are many things we can do to improve this. The challenge is loading and still getting all the info so we have a useful searchable dataset.

Will iterate towards this. This at least stops chronik from throwing errors and gives us some adjustable params.

Ultimately we would like

• Only render OrderBooks we can see
• Load all OrderBook data in the background
• Search enabled when all data has loaded, search quickl filters and renders only searched OrderBooks

This will take many steps though.

Test Plan:
npm test, npm start and observe loading behavior. It's not practical to specifically test these functions since we would need 100s or 1000s of mocks. Current test confirm that we still ultimately load everything.

deployed at https://cashtab-local-dev.netlify.app/

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Subscribers: emack, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D17500